sideroblastic anemia (redirected from Sideroblastic anaemias)

Sideroblastic Anemia 

Definition

Sideroblastic anemia is a term used to describe a group of rare blood disorders characterized by the bone marrow's inability to manufacture normal red blood cells.

Description

Named for the Greek words for iron and germ, sideroblastic anemia is one of the principal types of iron-utilization anemia. Abnormal, iron-saturated red cells are present in the blood of people who have this disease. Although the iron circulates normally from the plasma to the bone marrow, where new red blood cells are created, it is not properly incorporated into new red blood cells.

Sideroblastic anemia can be inherited, but the disease is usually acquired as a result of illness or exposure to toxic substances.

Sideroblastic anemia is a disease of adults.

Causes and symptoms

The cause of sideroblastic anemia cannot always be identified. Drug toxicity, alcohol abuse, and lead poisoning are common causes of this condition.

Sideroblastic anemia is also associated with:

• leukemia
• lymphoma (cancer of the lymph glands)
• myeloma (cancer of the bone marrow)
• rheumatoid arthritis, and other inflammatory diseases

Symptoms of sideroblastic anemia are the same as symptoms of the disease that causes the condition, as well as anemia

Complications

Possible complications of sideroblastic anemia include:

• congestive heart failure
• diabetes mellitus
• enlargement of the liver and spleen
• formation of liver nodules and scar tissue
• irregular heartbeat
• recurring inflammation of the sac that surrounds the heart
• secondary hypopituitarism (dwarfism)
• skin darkening
• underactivity of the thyroid gland

Diagnosis

Blood tests are used to examine the appearance and other characteristics of red cells and to measure the amount of iron in the blood. Bone marrow biopsy is also used.

Treatment

Acquired sideroblastic anemia may be cured when the condition that causes it is treated or removed.

If the cause of a patient's anemia cannot be determined, blood transfusions may be necessary. Medications are prescribed to stimulate excretion or excess iron that accumulates as a result of these transfusions.

In rare instances, treatment with oral pyridoxine (a B-complex vitamin) benefits patients whose sideroblastic anemia was present at birth. This treatment improves the condition of some patients but does not cure the anemia.

Prognosis

Sideroblastic anemia of unknown origin may lead to leukemia. It may take as long as 10 years for this disease progression to take place.

Resources

Organizations

Leukemia Society of America, Inc. 600 Third Ave., New York, NY 10016. (800) 955 4572. http://www.leukemia.org.

National Heart, Lung and Blood Institute. P.O. Box 30105, Bethesda, MD 20824-0105. (301) 251-1222. http://www.nhlbi.nih.gov.

National Organization for Rare Disorders. P.O. Box 8923, New Fairfield, CT 06812-8923. (800) 999-6673. http://www.rarediseases.org.

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anemia /ane·mia/ (ah-ne´me-ah) reduction below normal of the number of erythrocytes, quantity of hemoglobin, or the volume of packed red cells in the blood; a symptom of various diseases and disorders.ane´mic

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achrestic anemia  any of various types of megaloblastic anemia resembling pernicious anemia but unresponsive to therapy with vitamin B12.

aplastic anemia  a diverse group of anemias characterized by bone marrow suppression with replacement of the hematopoietic cells by fat, which causes pancytopenia, often accompanied by granulocytopenia and thrombocytopenia.

autoimmune hemolytic anemia  AIHA; a general term covering a large group of anemias involving autoantibodies against red cell antigens; they may be idiopathic or may have any of a number of causes, including autoimmune disease, hematologic neoplasms, viral infections, or immunodeficiency disorders.

aregenerative anemia  anemia characterized by bone marrow failure, so that functional marrow cells are regenerated slowly or not at all.

Blackfan-Diamond anemia  congenital hypoplastic a. (1).

congenital hypoplastic anemia 

1. a progressive anemia of unknown etiology seen in the first year of life, with deficiency of red cell precursors in an otherwise normally cellular bone marrow; it is unresponsive to hematinics.

2. Fanconi's syndrome (1).

congenital nonspherocytic hemolytic anemia  any of a heterogeneous group of inherited anemias characterized by shortened red cell survival, lack of spherocytosis, and normal osmotic fragility with erythrocyte membrane defects, multiple intracellular enzyme deficiencies or other defects, or unstable hemoglobins.

Cooley's anemia  thalassemia major.

drug-induced immune hemolytic anemia  immune hemolytic anemia produced by drugs, classified as the penicillin type, in which the drug induces the formation of specific antibodies; the methyldopa type, in which the drug induces the formation of anti-Rh antibodies; and the stibophen type, in which circulating drug-antibody complexes bind to red cells.

equine infectious anemia  a viral disease of equines, with recurring malaise and abrupt temperature rises, weight loss, edema, and anemia; transmission to humans has been suggested, in whom it causes anemia, neutropenia, and relative lymphocytosis.

Fanconi's anemia  Fanconi's syndrome (1).

hemolytic anemia  any of a group of acute or chronic anemias, inherited or acquired, characterized by shortened survival of mature erythrocytes and inability of bone marrow to compensate for the decreased life span.

hereditary iron-loading anemia  hereditary sideroblastic a.

hereditary sideroachrestic anemia  hereditary sideroblastic a.

hereditary sideroblastic anemia  an X-linked anemia characterized by ringed sideroblasts, hypochromic, microcytic erythrocytes, poikilocytosis, weakness, and later by iron overload.

hookworm anemia  hypochromic microcytic anemia resulting from infection with Ancylostoma or Necator; see also under disease.

hypochromic anemia  that characterized by a disproportionate reduction of red cell hemoglobin and an increased area of central pallor in the red cells.

hypoplastic anemia  that due to varying degrees of erythrocytic hypoplasia without leukopenia or thrombocytopenia.

iron deficiency anemia  a form characterized by low or absent iron stores, low serum iron concentration, low transferrin saturation, elevated transferrin, low hemoglobin concentration or hematocrit, and hypochromic, microcytic red blood cells.

macrocytic anemia  a group of anemias of varying etiologies, marked by larger than normal red cells, absence of the customary central area of pallor, and an increased mean corpuscular volume and mean corpuscular hemoglobin.

Mediterranean anemia  thalassemia major.

megaloblastic anemia  any anemia characterized by megaloblasts in the bone marrow, such as pernicious a.

microcytic anemia  that marked by decrease in size of the red cells.

myelopathic anemia , myelophthisic anemia leukoerythroblastosis.

normochromic anemia  anemia in which the hemoglobin content of the red cells as measured by the MCHC is in the normal range.

normocytic anemia  that marked by a proportionate decrease in the hemoglobin content, the packed red cell volume, and the number of erythrocytes per cubic millimeter of blood.

pernicious anemia  megaloblastic anemia, most commonly affecting older adults, due to failure of the gastric mucosa to secrete adequate and potent intrinsic factor, resulting in malabsorption of vitamin B12.

polar anemia  an anemic condition that occurs during exposure to low temperature; initially microcytic, but subsequently becoming normocytic.

pure red cell anemia  anemia characterized by absence of red cell precursors in the bone marrow; the congenital form is called congenital hypoplastic a.

refractory normoblastic anemia  refractory sideroblastic a.

refractory sideroblastic anemia  a sideroblastic anemia clinically similar to the hereditary sideroblastic form but occurring in adults and often only slowly progressive. It is unresponsive to hematinics or to withdrawal of toxic agents or drugs and may be preleukemic.

sickle cell anemia  an autosomal dominant type of hemolytic anemia, seen primarily in those of West African descent, and less often in the Mediterranean basin and a few other areas; it is caused by hemoglobin S with abnormal erythrocytes (sickle cells) in the blood. Homozygous individuals have the full-blown syndrome with accelerated hemolysis, increased blood viscosity and vaso-occlusion, arthralgias, acute attacks of abdominal pain, and ulcerations of the lower limbs; some have periodic attacks of sickle cell crises. The heterozygous condition is called sickle cell trait and is usually asymptomatic.

sideroachrestic anemia  sideroblastic a.

sideroblastic anemia  any of a group of anemias that may have diverse clinical manifestations; commonly characterized by large numbers of ringed sideroblasts in the bone marrow, ineffective erythropoiesis, variable proportions of hypochromic erythrocytes in the peripheral blood, and usually increased levels of tissue iron.

sideropenic anemia  a group of anemias marked by low levels of iron in the plasma; it includes iron deficiency anemia and the anemia of chronic disorders.

spur cell anemia  anemia in which the red cells have a bizarre spiculated shape and are destroyed prematurely, primarily in the spleen; it is an acquired form occurring in severe liver disease and represents an abnormality in the cholesterol content of the red cell membrane.

toxic hemolytic anemia  that due to toxic agents, including drugs, bacterial lysins, and snake venoms.

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sid·er·o·blas·tic anemia (sdr--blstk)

n.

Refractory anemia marked by sideroblasts in the bone marrow. Also called sideroachrestic anemia.

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sideroblastic anemia

[sid′ərōblas′tik]

Etymology: Gk, sideros, iron, blastos, germ

a heterogeneous group of chronic hematologic disorders characterized by normocytic or slightly macrocytic anemia, hypochromic and normochromic red blood cells, and decreased erythropoiesis and hemoglobin synthesis. The red blood cells contain a perinuclear ring of iron-stained granules. The condition may be acquired or hereditary and may be primary or secondary to another condition. The cause of the disease is not understood. Treatment may include extract of liver, pyridoxine, folic acid, and blood transfusion. Also spelled sideroblastic anaemia. Compare iron deficiency anemia, siderosis.

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anemia [ah-ne´me-ah]

a condition in which there is reduced delivery of oxygen to the tissues; it is not actually a disease but rather a symptom of any of numerous different disorders and other conditions. The World Health Organization has defined anemia as a hemoglobin concentration below 7.5 mmol/L (12 g/dL) in women and below 8.1 mmol/L (13 g/dL) in men.

 Peripheral blood smears from a patient with megaloblastic anemia (left) and from a normal subject (right), both at the same magnification. The smear from the patient shows variation in the size and shape of erythrocytes and the presence of macro-ovalocytes. From Goldman and Bennett, 2000.

Some types of anemia are named for the factors causing them: poor diet (nutritional anemia), excessive blood loss (hemorrhagic anemia), congenital defects of hemoglobin (hypochromic anemia), exposure to industrial poisons, diseases of the bone marrow (aplastic anemia and hypoplastic anemia), or any other disorder that upsets the balance between blood loss through bleeding or destruction of blood cells and production of blood cells. Anemias can also be classified according to the morphologic characteristics of the erythrocytes, such as size (microcytic, macrocytic, and normocytic anemias) and color or hemoglobin concentration (hypochromic anemia). A type called hypochromic microcytic anemia is characterized by very small erythrocytes that have low hemoglobin concentration and hence poor coloration. Data used to identify anemia types include the erythrocyte indices: (1) mean corpuscular volume (MCV), the average erythrocyte volume; (2) mean corpuscular hemoglobin (MCH), the average amount of hemoglobin per erythrocyte; and (3) mean corpuscular hemoglobin concentration (MCHC), the average concentration of hemoglobin in erythrocytes. adj., adj ane´mic.

Symptoms. Mild degrees of anemia often cause only slight and vague symptoms, perhaps nothing more than easy fatigue or a lack of energy. As the condition progresses, more severe symptoms may be experienced, such as shortness of breath, pounding of the heart, and a rapid pulse; these are caused by the inability of anemic blood to supply the body tissues with enough oxygen. Pallor, particularly in the palms of the hands, the fingernails, and the conjunctiva (the lining of the eyelids), may also indicate anemia. In very advanced cases, swelling of the ankles and other evidence of heart failure may appear.

Common Causes of Anemia. Loss of Blood (Hemorrhagic Anemia): If there is massive bleeding from a wound or other lesion, the body may lose enough blood to cause severe and acute anemia, which is often accompanied by shock. Immediate transfusions are generally required to replace the lost blood. Chronic blood loss, such as excessive menstrual flow, or slow loss of blood from an ulcer or cancer of the gastrointestinal tract, may also lead to anemia. These anemias disappear when the cause has been found and corrected. To help the blood replenish itself, the health care provider may prescribe medicines containing iron, which is necessary to build hemoglobin, and foods with high iron content, such as kidney and navy beans, liver, spinach, and whole wheat bread.

Dietary Deficiencies and Abnormalities of Red Blood Cell Production (Nutritional Anemia, Aplastic Anemia, and Hypoplastic Anemia): Anemia may develop if the diet does not provide enough iron, protein, vitamin B₁₂, and other vitamins and minerals needed in the production of hemoglobin and the formation of erythrocytes. The combination of poor diet and chronic loss of blood makes for particular susceptibility to severe anemia. Anemias associated with folic acid deficiency are very common.

Excessive Destruction of Red Blood Cells (hemolytic anemia): Anemia may also develop related to hemolysis due to trauma, chemical agents or medications (toxic hemolytic anemia), infectious disease, isoimmune hemolytic reactions, autoimmune disorders, and the paroxysmal hemoglobinurias.

Patient Care. Assessment of patients with some form of anemia will depend to some extent on the specific type of blood dyscrasia presented. In general, these patients do share some common problems requiring special assessment skills and interventions. Anemia can affect many different body systems

(see table). Although pallor of the skin is a sign of anemia, it is not the most reliable sign; many other factors can affect complexion and skin color. Jaundice of the skin and sclera can occur as a result of hemolysis and the release of bilirubin into the blood stream, where it eventually finds its way into the skin and mucous membranes. (See also jaundice.) Bleeding under the skin and bruises in response to the slightest trauma often are present in anemic and leukemic patients. A bluish tint to the skin (cyanosis) can indicate hypoxia due to inadequate numbers of oxygen-bearing erythrocytes.

Activity intolerance is a common problem for patients with anemia. Physical activity increases demand for oxygen, but if there are not enough circulating erythrocytes to provide sufficient oxygen, patients become physically weak and unable to engage in normal physical activity without experiencing profound fatigue. This can result in some degree of self-care deficit as the fatigue interferes with the patient's ability to carry on regular or enjoyable activities.

acute posthemorrhagic anemia hemorrhagic anemia.

aplastic anemia see aplastic anemia.

autoimmune hemolytic anemia (AIHA) an acquired disorder characterized by hemolysis due to the production of autoantibodies against one's own red blood cell antigens.

Blackfan-Diamond anemia congenital hypoplastic anemia (def. 1).

congenital hypoplastic anemia

idiopathic progressive anemia occurring in the first year of life, without leukopenia and thrombocytopenia; it is due to an isolated defect in erythropoiesis and is unresponsive to hematinics, requiring multiple blood transfusions to sustain life. For those responding to steroid therapy the prognosis is good. Called also Blackfan-Diamond anemia or syndrome, Diamond-Blackfan anemia or syndrome, and erythrogenesis imperfecta.

Fanconi's syndrome (def. 1).

Cooley's anemia tthalassemia major.

deficiency anemia nutritional anemia.

Diamond-Blackfan anemia congenital hypoplastic anemia (def. 1).

drug-induced hemolytic anemia (drug-induced immune hemolytic anemia) a form of immune hemolytic anemia induced by the taking of drugs, involving one of four different mechanisms:

Immune complex problems: Ingestion of any of a large number of drugs is followed by immunization and the formation of a soluble drug–anti-drug complex that adsorbs nonspecifically to the erythrocyte surface.

Drug absorption: Drugs bind firmly to erythrocyte membrane proteins, inducing the formation of specific antibodies; the drug most commonly associated with this mechanism is penicillin.

Membrane modification: A nonimmunologic mechanism whereby the drug involved is able to modify erythrocytes so that plasma proteins can bind to the membrane.

Autoantibody formation: Methyldopa (Aldomet) induces the production of autoantibodies that recognize erythrocyte antigens and are serologically indistinguishable from those seen in patients with warm autoimmune hemolytic anemia.

Fanconi's anemia (Fanconi's hypoplastic anemia) Fanconi's syndrome (def. 1).

hemolytic anemia see hemolytic anemia.

hemorrhagic anemia anemia caused by the sudden and acute loss of blood; called also acute posthemorrhagic anemia.

hypochromic anemia anemia in which the decrease in hemoglobin is proportionately much greater than the decrease in number of erythrocytes.

hypochromic microcytic anemia any anemia with microcytes that are hypochromic (reduced in size and in hemoglobin content); the most common type is iron deficiency anemia.

hypoplastic anemia anemia due to incapacity of blood-forming organs.

immune hemolytic anemia an acquired hemolytic anemia in which a hemolytic response is caused by isoantibodies or autoantibodies produced on exposure to drugs, toxins, or other antigens. See also autoimmune hemolytic anemia, drug-induced immune hemolytic anemia, and erythroblastosis fetalis.

iron deficiency anemia a type of hypochromic microcytic anemia that results from the presence of greater demands on stored iron than can be met, usually because of chronic blood loss, dietary deficiency, or defective absorption; it is characterized by low or absent iron stores, low serum iron concentration, low transferrin saturation, elevated transferrin (total iron-binding capacity), and low hemoglobin concentration or hematocrit. Iron deficiency anemia is the most common nutritional disorder in the United States.

macrocytic anemia anemia characterized by macrocytes (erythrocytes much larger than normal).

Mediterranean anemia thalassemia major.

megaloblastic anemia any of various anemias characterized by the presence of megaloblasts in the bone marrow or blood; the most common type is pernicious anemia.

microangiopathic hemolytic anemia thrombotic thrombocytopenic purpura.

microcytic anemia anemia characterized by microcytes (erythrocytes smaller than normal); see also hypochromic microcytic anemia and microcythemia.

myelopathic anemia (myelophthisic anemia) leukoerythroblastosis.

normochromic anemia that in which the hemoglobin content of the red blood cells is in the normal range.

normocytic anemia anemia characterized by proportionate decrease in hemoglobin, packed red cell volume, and number of erythrocytes per cubic millimeter of blood.

nutritional anemia anemia due to a deficiency of an essential substance in the diet, which may be caused by poor dietary intake or by malabsorption; called also deficiency anemia.

pernicious anemia see pernicious anemia.

sickle cell anemia see sickle cell anemia.

sideroachrestic anemia (sideroblastic anemia) any of a heterogenous group of acquired and hereditary anemias with diverse clinical manifestations, commonly characterized by large numbers of sideroblasts in the bone marrow, ineffective erythropoiesis, variable proportions of hypochromic erythrocytes in the peripheral blood, and usually increased levels of tissue iron.

spur cell anemia anemia in which the erythrocytes are acanthocytes (spur cells) and are destroyed prematurely, primarily in the spleen; it is an acquired form occurring in severe liver disease in which there is increased serum cholesterol and increased uptake of cholesterol into the erythrocyte membrane, causing the abnormal shape.